1. Field of the Invention
The present invention relates to an airbag for a head-protecting airbag system mountable in a vehicle, such as an automobile. The airbag is folded up and accommodated in the upper edge side of an opening in the interior of the automobile. This airbag is inflatable to cover an opening when fed with an inflation gas.
2. Description of Related Art
An airbag for a head-protecting airbag system is described in Unexamined Published International Patent WO96/26087 and Unexamined Published UK Patent Application No. 2314300. This airbag has a gas inlet portion and an inflatable portion.
The gas inlet portion is a portion for introducing an inflation gas into the airbag. The inflatable portion is formed into a bag shape and is inflated to cover the opening of the interior when fed with the inflation gas. The inflatable portion is provided with a plurality of vertically extending inflating chambers which are arranged in a horizontal direction relative to each other. Between the individual inflating chambers, there are vertically arranged uninflating portions. The gas inlet portion is arranged to extend from the front end side of the airbag to the upper edge side of the inflatable portion. Moreover, the gas inlet portion extends so long in the longitudinal (fore and aft) direction as to communicate with the individual inflating chambers.
The airbag thus constructed is inflated in the following manner. When the individual inflating chambers are inflated, the distance between the uninflating portions is narrowed. Therefore, a forward or backward tension acts on the inflatable portion. As a result, the airbag can suppress the movement of the inflatable portion to the outside of the vehicle while restraining the passenger.
In the airbag of the prior art, there is room for improvement in intensifying the tension to be established on the lower edge side.
In the airbag thus constructed, on the other hand, the inflation gas floes downward into the individual inflating chambers through the gas inlet portion extending in the longitudinal direction.
However, the gas inlet portion is arranged on a peripheral edge of an opening of the vehicle, requiring a long time for the individual inflating chambers to be inflated to some extent. In the airbag of the prior art, therefore, there is room for improvement in the area of forming the airbag quickly, and capably restraining a passenger before the inflation of the airbag is complete.
A first object of the invention is to provide an airbag for a head-protecting airbag system capable of exhibiting a tension especially on the lower edge side of the airbag body when the airbag is inflated. Specifically, the object of the invention is to provide an airbag for a head-protecting airbag system which prevents the passenger restraining area from moving to the exterior of the vehicle when the airbag is inflated.
A second object of the invention is to provide an airbag for a head protecting airbag system capable of arranging the passenger restraining area quickly and widely before inflation is complete.
The aforementioned first object can be achieved by an airbag for a head protecting airbag system having the following construction. The airbag is folded up and accommodated along an upper interior edge of a vehicle and is developed and inflated to cover said interior opening. The airbag comprises a flexible airbag body and a flexible belt portion. The airbag body includes an inflatable portion adapted to be inflated to cover said interior opening when said airbag is developed and inflated. The inflatable portion includes a longitudinal rod portion adapted to be inflated substantially into a vertically oriented column shape. The longitudinal rod portion is arranged forward or rear of the inflatable portion. The flexible belt portion is joined at its proximal portion to the peripheral edge of said longitudinal rod portion and fixed at its distal end portion on the vehicle so that upon inflation of the inflatable portion, the lower end side of said longitudinal rod portion may be turned, said the flexible belt guides the longitudinal rod portion in the forward or backward direction away from said inflatable portion.
In the aforementioned airbag for the head-protecting airbag system, during inflation, the inflatable portion of the airbag body is developed and inflated to arrange the longitudinal rod portion into a substantially vertically oriented column. Then, the belt portion guides the longitudinal rod portion so that the upon inflation of said inflatable portion, the longitudinal rod portion generally pivots about an end thereof into a substantially vertical orientation.
At this time, the longitudinal rod portion admits the inflation gas so that it is inflated substantially vertically in a rod shape, that is, it takes a rigid rod state. Therefore, the rod-shaped longitudinal rod portion receives the turning torque by the belt portion so that a tension by the belt portion acts on the lower edge of the airbag body.
In the airbag for the head-protecting airbag system according to the invention, therefore, the tension can be exhibited especially on the lower edge side of the airbag body when the airbag is inflated. In the airbag according to the invention, moreover, the area capable of restraining the passenger substantially does not move to the exterior of the vehicle. As a result, the airbag according to the invention can restrain the passenger properly substantially over its entire area.
Moreover, the length of said belt portion, as extended straight from the proximal portion to the distal end portion, is desirably made smaller than the distance which is measured in a predetermined state between the proximal portion to a fixing portion of the distal end portion on said opening peripheral edge. In this predetermined state, the airbag body is mounted on the vehicle, and is developed but not inflated.
The following actions and effects can be obtained when the airbag is constructed as described hereinbefore. Specifically, the belt portion can be short in length. During inflation, therefore, the turning torque can be reliably applied to the longitudinal rod portion. As a result, a high tension is applied to the lower edge side of the airbag body. Here, the belt portion has a short length. However, the belt portion and the airbag body are flexible. Therefore, the belt portion can be easily pulled out when the airbag is folded up and mounted in the vehicle. As a result, the distal end portion of the belt portion can be easily attached to the vehicle when the airbag is to be mounted on the vehicle.
On the other hand, the construction of the belt portion may be modified in the following manner. The belt portion may be joined at the proximal portion to the circumferential edge of the upper end of said longitudinal rod portion. On the other hand, the belt portion may be fixed at said distal end portion on the vehicle through an insert hole formed in the circumferential edge of the lower end of the longitudinal rod portion.
The following actions and effects can be obtained when the airbag is constructed as described hereinbefore. When the airbag is folded up and accommodated along an upper interior edge of the vehicle, the belt portion can be let out to the distal end portion through the insert hole. Therefore, even if the belt portion is shortened, the distal end portion of the belt portion can be easily fixed on the vehicle, and the belt portion can be shortened so that a high turning torque can be applied to the longitudinal rod portion during inflation. Without degrading the mounting workability on the vehicle, therefore, a high tension can be exhibited on the lower edge of the airbag body at the time of inflation.
Moreover, the construction of the belt portion may be modified in the following manner. The belt portion may be trifurcated to have three end portions. Two of the three end portions of said belt portion are joined proximalat the proximal portion to the upper and lower portions of the circumferential edge of the longitudinal rod portion. The remaining one of the three end portions of the belt portion is fixed at the distal end portion on the vehicle.
The following actions and effects can be obtained when the airbag is constructed as described hereinbefore. When the airbag is to be folded up and accommodated along the upper interior edge side of the vehicle, more specifically, the bifurcated proximal portions of the belt portion on the side of the longitudinal rod portion come closer to each other. Also, the belt portion from the proximal portion to the distal end portion is elongated. Therefore, the distal end portion of the belt portion is easily fixed on the vehicle. When the airbag is developed and inflated, on the other hand, the bifurcated proximal portion is vertically separated by the formation of the longitudinal rod portion. Also, the substantial length of the belt portion from the proximal portion to the distal end portion is reduced. This makes it possible to apply a high turning torque to the longitudinal rod portion. Without degrading the mounting workability on the vehicle, therefore, a high tension can be exhibited at the lower edge of the airbag body at the time of inflation.
The aforementioned second object can be achieved by the airbag for the head protecting airbag system having the following construction. The airbag is folded up and accommodated along the upper interior edge of the vehicle in the interior of a vehicle and is developed and inflated to cover the interior opening. The airbag has an inflatable portion and a gas inlet portion. The inflatable portion is formed into a bag shape, and is inflated to cover an interior opening of the vehicle. The gas inlet portion is arranged on one end side of the front end side or the rear end side of the inflatable portion for introducing an inflation gas into the inflatable portion. On the other hand, the inflatable portion includes a main chamber and upper and lower auxiliary chambers. The main chamber is arranged to extend along a substantially straight path and substantially horizontal direction from the gas inlet portion. The upper and lower auxiliary chambers are arranged over and below the main chamber, respectively, in communication with the end portion of the main inflating chamber, spaced from the gas inlet portion.
In the aforementioned airbag for the head-protecting airbag system, the incoming inflation gas is introduced into the main chamber of the inflatable portion through the gas inlet portion. The inflation gas is further introduced from the main chamber into the upper and lower auxiliary chambers.
Specifically, the main inflating chamber is inflated before the airbag finishes inflating by the inflow of the inflation gas into the upper and lower auxiliary chambers. The main chamber is arranged to extend substantially along a straight path and substantially horizontal direction from the gas inlet portion. Therefore, the main chamber is quickly inflated. On the other hand, the main chamber is arranged long in the longitudinal (fore and aft) direction at the vertically intermediate portion of the upper and lower auxiliary chambers, that is, at the vertically intermediate portion of the inflatable portion. Therefore, the airbag is inflated over a wide area by the main chamber.
In the airbag for the head-protecting airbag system according to the present invention, therefore, the main chamber can be inflated quickly and widely before inflation is complete. In the airbag of the present invention, moreover, the passenger can be quickly and widely restrained by the area of the main chamber before the inflation is complete.
The aforementioned construction of the airbag may be modified in the following manner. An uninflating portion is arranged on the end side of the main chamber, spaced from the gas inlet portion, and extending vertically over the upper and lower auxiliary inflating chambers. On the other hand, the upper and lower auxiliary chambers have inflation gas inlets arranged to confront each other vertically at the end portion of the main chamber, spaced from the gas inlet portion.
The following actions and effects can be obtained when the airbag is constructed as described hereinbefore. Specifically, the inflation gas having passed through the main chamber is vertically separated by the guide of the vertically extending uninflating portion. And, the inflation gas flows through the individual inlets into the upper and lower auxiliary chambers. As a result, the upper and lower auxiliary chambers of the airbag are smoothly inflated.
With the construction thus far described, moreover, as to the inlets of the inflation gas of the upper and lower auxiliary chambers, the opening area of the lower auxiliary chamber is made larger than that of the upper auxiliary chamber.
In this airbag, the lower auxiliary chamber is inflated more quickly than the upper auxiliary chamber. The lower auxiliary chamber is spaced from a peripheral edge of an opening of the vehicle, and can restrain the passenger more smoothly than the upper auxiliary inflating chamber. In this airbag, therefore, it is possible to better improve passenger restraining performance before inflation is complete.